The Youth Workers' Collective wants the sale of legal highs banned within 500m of schools, playgrounds and churches, and a 300m gap between shops licensed to sell the drugs.

However, council solicitor Kaye McIlveney, who wrote the draft policy, said the Medical Officer of Health had said 50m was an "appropriate degree of separation between an outlet and a sensitive site" in a submission to the Nelson City Council when it was considering the same issue.

A 500m exclusion zone would end up prohibiting the sale of legal highs in a town the size of Blenheim, and the council did not have this power under the Psychoactive Substances Act, she said. She pointed out that the collective's proposal would allow for sales in residential areas, but the policy before council would restrict sales to central Blenheim.

The youth workers also proposed a ban on sales outside the hours of 9am to 3pm, but Ms McIlveney said the Psychoactive Substances Act 2013 did not allow the council to impose time restrictions on drug sales.

Under the act, dairies, convenience stores, supermarkets, petrol stations and anywhere that sells alcohol are banned from selling legal highs.